Volcanoes

When sediments were being deposited and mineral deposits were forming in the Ocoee Basin, volcanoes were erupting in areas that are now Virginia, the Carolinas, and Georgia. Lava from some volcanoes flowed in slow-moving sheets like lava from the Hawaiian volcanoes, but other eruptions were explosive, like Mount St. Helens.  Although volcanic activity ended hundreds of millions of years ago, rocks that formed from these ancient volcanoes are still visible.  Fragments that erupted from ancient volcanoes and minerals that filled holes where gas bubbles had escaped can be seen in some rocks at White Top Mountain in the Mount Rogers National Recreation Area of southern Virginia.

Amphibolites, that were most likely sea floor basalts before being metamorphosed during the Paleozoic, are common, and locally areally extensive in the Eastern Blue Ridge province.  These basalts likely formed in a rift environment similar to the Ocoee Basin.  It is important to understand that amphibolites weather to more basic soil types, and can support different plant communities than those that dominate on soil types derived from less fertile, weathered metasedimentary rocks.